Reuse existing assertions inside custom assertion?

[lonix1]

I followed the docs to write custom assertions. But I found an edge case that is not covered in the docs or past issues/discussions.

Let's say I have a container type Container and I want to assert this:

Container.Foo.Value.Should().BeSameAs(otherValue);

I want to write a custom assertion like so:

Container.Should().HaveValueSameAs(otherValue);

I wrote a custom assertion that does that. But I had to duplicate all the Equals(), ==, ReferenceEquals(), etc., that this library already does very well.

Is it possible to "reuse" built-in assertions when writing my custom assertion?

public AndConstraint<ContainerAssertions> HaveValueSameAs(object other, string because = "", params object[] becauseArgs)
{
  Execute.Assertion
    .BecauseOf(because, becauseArgs)
    //...reuse Be() / BeSameAs() / BeEquivalentTo() / etc...
    .FailWith("some message");

  return new AndConstraint<ContainerAssertions>(this);
}

[dennisdoomen]

Why not use the FA assertions directly in your HaveValueSameAs method?

[lonix1]

Such a simple solution, why didn't I think of it?! :)

[lonix1]

For everyone else, the full solution is:

public AndConstraint<ContainerAssertions> HaveValueSameAs(object other, string because = "", params object[] becauseArgs)
{
  // you can have custom assertions before
  Execute.Assertion
    .BecauseOf(because, becauseArgs)
    //...stuff
    .FailWith("some message");

  // use built-ins assertions
  other.Should().Foo().And.Bar();

  // you can have custom assertions after
  Execute.Assertion
    .BecauseOf(because, becauseArgs)
    //...stuff
    .FailWith("some message");

  // and remember to return the constraint so chaining still works:
  return new AndConstraint<ContainerAssertions>(this);
}